1. Field of the Invention
The present invention relates to an image recording apparatus and an electronic still camera.
2. Related Background Art
There is already known an electronic still camera, in which the image of an object is converted by a solid-state image pickup device into an electric signal and recorded on a recording medium. As the recording medium for the obtained image information, there was initially proposed a small flexible magnetic disk, but an apparatus utilizing a semiconductor memory was also proposed later, due to the increase in the capacity thereof. Also compact rigid disk devices (2 inches or smaller) which have been commercialized recently are attracting attention as the recording medium for the electronic still camera because of their compactness.
In general, the electronic still camera is provided with a single shot mode in which a single object image is taken by a single shutter releasing operation, as in the conventional still camera employing the silver halide film as the recording medium, and a continuous shot mode in which the object image is taken in succession at a predetermined interval while the shutter release button is kept depressed.
As the amount of information to be recorded per image phane is relatively large, the transmission or writing speed to the flexible magnetic disk, solid-state memory or rigid disk constituting the final recording medium is slower than the processing speed in the image pickup device or in the circuit for processing the output signals thereof. For practically increasing the transmission speed, there has been proposed a configuration in which a buffer memory capable of temporarily storing the image information of plural frames is provided for buffering the image information obtained in the continuous shot mode.
In such electronic still camera, however, it is not acceptable to increase the volume of the camera by assigning a large space to such buffer memory, since such electronic still camera has to be handily portable as a replacement for the conventional camera utilizing the silver halide film. Also the semiconductor memories are costly if it is used in a large quantity, even though memory devices of a large memory capacity have become available by the advancement in the level of integration.
For these reasons, the capacity of the buffer memory has to be limited at a certain level, but, if the capacity is not enough, the remaining capacity of the buffer memory may become deficient in the course of a continuous phototaking operation so that the image recording may become impossible.